When it comes to manufacturing large hollow plastic parts, nothing beats the process of rotomolding. Compared to other molding or casting processes like injection or blow molding, rotomolding is exceptionally cost efficient and the products produced are also of better quality.

Historical Origin of Rotomoulding Process

Rotational moulding process is an ancient concept and it has a long history to go with. Centuries ago, Egyptians used to manufacture ceramics using rotational casting process. Moreover, moulding processes were also used 100 of years ago by the Swiss to develop hollow chocolate eggs.

For the first time in USA, somewhere in between 1940-1950, the rotational moulding process was designed for plastics. It was regarded as a very slow process and did not get popular. Although, over the years of process control improvements as well as plastic powder development, this process has gained popularity & has been of much use in various industrial segments.

By the late 1950, the rotational moulding process was better understood and found its applications in road cones, marine buoys & car armrests. Also, this process was used for manufacturing doll heads. Moreover, the process led to the development of other plastic toys. In the ancient times, the heated hollow mold was filled with a shot or charge weight of material and then rotated slowly. The rotation caused the softened material to disperse & stick to the mold walls. Continuous rotation of the mold results in uniform thickness of the products.
The popularity led to the development of hi-tech machinery. Also, new system of heating was introduced, called indirect high velocity air system. In 1960s, Engel process was developed in Europe which allowed the creation of large hollow containers in low density. By the 1980, this process became quite popular and was being used in varied industrial segments across the world. In response to the increasing demand, new materials stated becoming easily available for the process. In the year 1984, rotomoulding became the most preferable process for manufacturing of inexpensive whitewater & sea kayaks.

For this process, various types of rotational moulding machines are available in the market in different specifications in terms of size, capacity, etc. A typical rotomoulding machine comprises molds, oven, cooling chamber and mold spindles.

Below mentioned are the different types of rotational moulding machines used by various manufacturing companies/ industries across the globe: